Standard C++	Library
 		 Copyright 1996, Rogue Wave Software, Inc.

 NAME

   num_get - Numeric formatting facet for input.

 SYNOPSIS

   #include <locale>
   template <class charT, class InputIterator > class num_get;

 DESCRIPTION

   The num_get provides facilities for formatted	input of numbers.
   basic_istream	and all	other input-oriented streams use this facet to imple-
   ment formatted numeric input.

 INTERFACE

   template <class charT, class InputIterator = istreambuf_iterator<charT> >
   class	num_get	: public locale::facet {
   public:
    typedef charT	    char_type;
    typedef InputIterator    iter_type;
    explicit num_get(size_t refs	= 0);
    iter_type get(iter_type, iter_type, ios_base&,
 		 ios_base::iostate&, bool&)	     const;
    iter_type get(iter_type, iter_type, ios_base& ,
 		 ios_base::iostate&, long&)	     const;
    iter_type get(iter_type, iter_type, ios_base&,
 		 ios_base::iostate&, unsigned short&) const;
    iter_type get(iter_type, iter_type, ios_base&,
 		 ios_base::iostate&, unsigned int&)  const;
    iter_type get(iter_type, iter_type, ios_base&,
 		 ios_base::iostate&, unsigned long&) const;
    iter_type get(iter_type, iter_type, ios_base&,
 		 ios_base::iostate&, float&)	     const;
    iter_type get(iter_type, iter_type, ios_base&,
 		 ios_base::iostate&, double&)	     const;
    iter_type get(iter_type, iter_type, ios_base&,
 		 ios_base::iostate&, long double&)   const;
    static locale::id id;

   protected:
     ~num_get();	 // virtual
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
 			    ios_base::iostate&,	bool&) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
 			    ios_base::iostate&,	long&) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
 			    ios_base::iostate&,
 			    unsigned short&) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
 			    ios_base::iostate&,
 			    unsigned int&) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
 			    ios_base::iostate&,
 			    unsigned long&) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
 			    ios_base::iostate&,	float&)	const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
 			    ios_base::iostate&,	double&) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
 			    ios_base::iostate&,
 			    long double&) const;
   };

 TYPES

   char_type
      Type of character the facet is instantiated on.

   iter_type
      Type of iterator used to scan the character buffer.

 CONSTRUCTOR AND	DESTRUCTOR

   explicit num_get(size_t refs = 0)
      Construct a num_get facet.	 If the	refs argument is 0 then
      destruction of	the object is delegated	to the locale, or
      locales, containing it. This allows the user to ignore lifetime
      management	issues.	 On the	other had, if refs  is 1	then
      the object	must be	explicitly deleted; the locale will not do
      so.  In	this case, the object can be maintained across the
      lifetime of multiple locales.

   ~num_get();  // virtual and protected
      Destroy the facet

 FACET ID

   static locale::id id;
      Unique identifier for this	type of	facet.

 PUBLIC MEMBER FUNCTIONS

   The public members of	the num_get facet provide an interface to
   protected members.  Each public	member xxx has a corresponding
   virtual protected member do_xxx.  All work is delagated	to
   these protected members.  For instance, the	long version of	the
   public get function	simply calls its protected cousin
   do_get.

   iter_type
   get(iter_type	in, iter_type end, ios_base& io,
      ios_base::iostate&	err, bool& v)	       const;
   iter_type
   get(iter_type	in, iter_type end, ios_base& io,
      ios_base::iostate&	err, long& v)	       const;
   iter_type
   get(iter_type	in, iter_type end, ios_base& io,
      ios_base::iostate&	err, unsigned short& v)	const;
   iter_type
   get(iter_type	in, iter_type end, ios_base& io,
      ios_base::iostate&	err, unsigned int& v)  const;
   iter_type
   get(iter_type	in, iter_type end, ios_base& io,
      ios_base::iostate&	err, unsigned long& v) const;
   iter_type
   get(iter_type	in, iter_type end, ios_base& io,
      ios_base::iostate&	err, float& v)	       const;
   iter_type
   get(iter_type	in, iter_type end, ios_base& io,
      ios_base::iostate&	err, double& v)	       const;
   iter_type
   get(iter_type	in, iter_type end, ios_base& io,
      ios_base::iostate&	err, long double& v)   const;
      Each of the eight overloads of the	get function simply call the
      corresponding do_get function.

 PROTECTED MEMBER FUNCTIONS

   virtual iter_type
   do_get(iter_type in, iter_type end, ios_base&	io,
 	ios_base::iostate& err,	bool& v) const;
   virtual iter_type
   do_get(iter_type in, iter_type end, ios_base&	io,
 	ios_base::iostate& err,	long& v) const;
   virtual iter_type
   do_get(iter_type in, iter_type end, ios_base&	io,
 	ios_base::iostate& err,
 	unsigned short&	v) const;
   virtual iter_type
   do_get(iter_type in, iter_type end, ios_base&	io,
 	ios_base::iostate& err,
 	unsigned int& v) const;
   virtual iter_type
   do_get(iter_type in, iter_type end, ios_base&	io,
 	ios_base::iostate& err,
 	unsigned long& v) const;
   virtual iter_type
   do_get(iter_type in, iter_type end, ios_base&	io,
 	ios_base::iostate& err,	float& v) const;
   virtual iter_type
   do_get(iter_type in, iter_type end, ios_base&	io,
 	ios_base::iostate& err,	double&	v) const;
   virtual iter_type
   do_get(iter_type in, iter_type end, ios_base&	io,
 	ios_base::iostate& long	double&	v) const;

      The eight overloads of the	do_get member function all take	a
      sequence of characters	[int,end), and extract a numeric
      value.	 The numeric value is returned in v.   The io argument
      is used to obtain	formatting information and the err argument
      is used to set error conditions in a calling stream.

 EXAMPLE

   //
   // numget.cpp
   //

   #include <sstream>

   int main ()
   {
    using namespace std;

   typedef istreambuf_iterator<char,char_traits<char> > iter_type;

    locale loc;
    ios_base::iostate state;
    bool	bval = false;
    long	lval = 0L;
    long	double ldval = 0.0;
    iter_type end;

     // Get a num_get facet
    const num_get<char,iter_type>& tg =
   #ifndef _RWSTD_NO_TEMPLATE_ON_RETURN_TYPE
    use_facet<num_get<char,iter_type> >(loc);
   #else
    use_facet(loc,(num_get<char,iter_type>*)0);
   #endif

     {
       // Build an istringstream	from the buffer	and construct
       // beginning and ending iterators	on it.
      istringstream ins("true");
      iter_type begin(ins);

       // Get a bool value
      tg.get(begin,end,ins,state,bval);
     }
    cout	<< bval	<< endl;
     {
       // Get a long value
      istringstream ins("2422235");
      iter_type begin(ins);
      tg.get(begin,end,ins,state,lval);
     }
    cout	<< lval	<< endl;
     {
       // Get a long double value
      istringstream ins("32324342.98908");
      iter_type begin(ins);
      tg.get(begin,end,ins,state,ldval);
     }
    cout	<< ldval << endl;
    return 0;
   }

 SEE ALSO

   locale, facets, num_put, numpunct, ctype

 STANDARDS CONFORMANCE
   ANSI X3J16/ISO WG21 Joint C++	Committee